Polyamide compounds

ABSTRACT

An acid-dyeable polyester composition comprising (a) polyester and (b) secondary amine or secondary amine salt in an amount effective to promote acid-dyeability. The acid-dyeable polyester composition may be prepared by melt blending: the polyester; and polymeric additive prepared from (i) triamine containing secondary amine or secondary amine salt unit(s) and (ii) one or more other monomer and/or polymer units. One polymeric additive comprises polyamide selected from the group consisting of poly-imino-bisalkylene-terephthalamide, -isophthalamide and -1,6-naphthalamide, and salts thereof. Also, the polymeric additive, the blends, shaped articles (e.g., fibers and films), processes of dyeing, and processes for preparing an acid dyeable polyester composition.

PRIORITY

This application claims priority from U.S. provisional patentapplication Ser. No. 60/165,373, filed Nov. 12, 1999, and is adivisional of U.S. patent application Ser. No. 09/708,209, filed Nov. 8,2000, now U.S. Pat. No. 6,576,340 both of which are incorporated hereinby reference.

FIELD OF THE INVENTION

This invention relates to acid-dyeable polyester compositions suitablefor use in manufacturing fibers, fabrics, films and other usefularticles, the articles, and methods of making such compositions andarticles. The acid-dyeable polyester compositions contain a polymericadditive composition that has secondary nitrogen groups. The secondarynitrogen groups provide improved acid dyeability. This invention alsorelates to the polymeric additive composition.

BACKGROUND OF THE INVENTION

Polyesters, especially polyalkylene terephthalates, have excellentphysical and chemical properties and have been widely used for resins,films and fibers. In particular, polyester fibers have a high meltingpoint, and can attain high orientation and crystallinity. Accordingly,polyesters have excellent fiber properties such as chemical, heat andlight stability, and high strength. However, polyesters, especiallypolyester fibers and fabrics, are difficult to dye. The molecularstructure and the high levels of orientation and crystallinity thatimpart the desirable properties to the polyester also contribute to aresistance to coloration by dye compounds. Also contributing to thedifficulty in dyeing polyester compositions is the characteristic thatpolyesters do not have dye sites within the polymer chain that arereactive to basic or acid dye compounds.

Blending of nylon 6 or nylon 6,6 with polyester has been proposed toobtain the benefits of the polyamide acid dye sites in the resultingcomposition. The high concentrations of polyamide that may be requiredto impart dyeability in the resulting polyester/polyamide copolymercomposition result in decreased physical properties in thepolyester/polyamide copolymer and difficulties in processing. Forexample, Canadian Patent No. 974340 discloses an acid-dyeable polyestercomposition using polyamides having cyclic, tertiary nitrogen-groupsincorporated into polyalkylene terephthalates by blending and extrudingthe two polymers, and reports that polyamide microfibrils form withinthe polyester matrix during filament extrusion operations when highpolyamide concentrations are used.

Commonly assigned U.S. Pat. Nos. 3,901,853, 4,001,189 and 4,001,190disclose that many methods have been proposed for improving theacid-dyeability of polyester fibers and filaments by co-polymerizationof nitrogen containing modifiers into the chains of polyester molecules,but that they have been inadequate for various reasons. U.S. Pat. Nos.3,901,853, 4,001,189 and 4,001,190 further disclose that in order toprovide good acid-dyeability, the modifier should contain a highly basicnitrogen atom that functions as a dye site but does not adversely affectmolecular weight or cause discoloration. Thermal stability,effectiveness at low concentrations and low volatility are importantproperties of the cyclic, tertiary 2,2,6,6 tetramethylpiperidine groupsthat are disclosed as nitrogen containing modifiers.

U.S. Pat. No. 3,867,478 discloses that the use of polyamides containingtertiary amino groups in polyesters results in brown, discolored fibersafter melt-blending and melt-spinning. The brightness of the dyed fibersis also reported as reduced. U.S. Pat. No. 3,867,478 discloses the useof phosphorus compounds to improve the dyeability of polyesterscontaining tertiary amino groups.

Japanese Kokai No. 47-32184 discloses that nitrogen containingpolyesters are difficult to acid-dye because the addition of sufficientnitrogen dye sites into the polymer causes coloring in the polymer anddecreases physical properties. Lower amounts of basic nitrogen inpolyesters are said to be insufficient to develop adsorption toward theacidic dye. The addition of benzene derivatives to the dye bath isproposed to improve the dyeability of the fibers.

Although, as described above, substantial work has been done withrespect to the use of tertiary amine compounds to enhance the dyeabilityof polyesters, secondary aliphatic amines have generally been used inpolymeric compositions as chain branching agents or crosslinkers becauseof their functionality. U.S. Pat. No. 4,145,473 to Samuelson, et al.discloses the use of bis-(hexamethylene)triamine as a branching agent toincrease the viscosity of polymer compositions used in melt spinningfibers.

U.S. Pat. No. 5,068,283 discloses a method for producing a thermoplasticresin wherein a saturated polyester resin and an epoxy group-containingethylene copolymer are melt-kneaded into a composition and then furthermelt kneaded with a polyfunctional compound which carries out a partialcross-linking reaction. The polyfunctional compounds may be an amine.However, as disclosed in U.S. Pat. No. 5,322,923, the presence ofstructural derivatives of bis-(hexamethylene)triamine in amounts greaterthan 0.5 weight % has been shown to cause an undesirable increase in theviscosity characteristics of copolyamides used as molding compositions.

Methods that relate to treating a polyester with a dye compositioncontaining nitrogen compounds, as opposed to including a nitrogencontaining additive in the polyester, have also been proposed. U.S. Pat.No. 3,932,126 discloses a process for acid dyeing shaped or preformedpolyester materials by applying an aqueous solution or printing paste ofone or more acid dyes, various organic nitrogen compounds and organiccarboxylic acids. The impregnated polyester material is dried and thenheated. The preferred organic nitrogen compounds include alkyleneamines,alkanolamines and alkylamines.

All of the aforementioned documents are incorporated herein byreference.

It is desirable to have acid-dyeable nitrogen-containing polyestercompositions which may be easily processed into fibers, films or othershaped articles and acid-dyed without expensive additives, specialsolutions, and/or complicated application procedures.

SUMMARY OF THE INVENTION

This invention is directed to an acid-dyeable polyester compositioncomprising (a) polyester and (b) secondary amine or secondary amine saltin an amount effective to promote acid-dyeability.

Preferably the acid-dyeable polyester composition is prepared by meltblending (a) polyester; and (b) polymeric additive prepared from (i)triamine containing secondary amine or secondary amine salt unit(s) and(ii) one or more other monomer and/or polymer units.

In another preferred embodiment, the acid-dyeable polyester compositionof claim 1 prepared by melt blending (a) a polyester; and (b) apolyamide or polyamide salt selected from the group consisting ofpoly-imino-bisalkylene-terephthalamide, -isophthalamide and-1,6-naphthalamide and salts thereof.

By “polyester” or “a polyester” applicant is referring to singlepolyester, or blends or mixtures of polyesters. This comment alsoapplies to “polymeric additive”, “polyamide”, “polyamide salt”, andother such terms that are used herein. Thus, for instance, if applicantrefers to a composition containing X mole % of a polyester, thecomposition may comprise X mole % of one polyester or X mole % total ofdifferent polyesters.

The polyester is selected from the group consisting of polyalkyleneterephthalate, polyalkylene naphthalate and polyalkylene isophthalate.

Preferably the acid-dyeable polyester composition comprises at leastabout 0.5 mole %, more preferably at least about 1 mole %, mostpreferably at least about 2 mole %, of secondary amine units. Preferablythe acid-dyeable polyester composition comprises less than about 15 mole%, more preferably less than about 10 mole %, and most preferably lessthan about 5 mole % of secondary amine units. This mole percentage iscalculated based upon the number of repeat units in the polyestercomposition, including the polyester and polymeric additive.

Preferably the polyester is selected from the group consisting ofpolyethylene terephthalate, polytrimethylene terephthalate andpolytetramethylene terephthalate, more preferably polytrimethyleneterephthalate.

The polyamide comprises a compound having the following formula:

Preferably A or B, which may be the same or different, are selected fromaliphatic or aromatic substituents.

Preferably n is at least 3, more preferably at least 10. Preferably n is30 or less, more preferably 20 or less. Most preferably n is 15.

Preferably a is at least 1, more preferably at least 3, most preferablyat least 5. Preferably a is 20 or less, more preferably 12 or less.

Preferably b is at least 1, more preferably at least 3, most preferablyat least 5. Preferably b is 20 or less, more preferably 12 or less.

Most preferably, A or B, which may be the same or different, areselected from alkyl and aryl and each may contain 0-20 alkyl units and0-3 aryl units, provided that each contains at least one aryl unit or atleast two alkyl units. The alkyl and aryl units may be substituted orunsubstituted, straight or branched, etc., as long as the substituent(s)and branches don't substantially interfere with dyeing or other fiberproperties (e.g., the chain may contain an ether group).

Preferably the polyamide is poly(6,6′-imino-bishexamethyleneterephthalamide) having repeat units according to the formula:

wherein n is preferably at least 3, and n is preferably 30 or less.

The polyester composition may be in the form of a fiber, such as amonocomponent or bicomponent fiber, or a yarn made therefrom. Thepolyester composition may alternatively be in the form of a film or filmlayer.

In one preferred embodiment, the polyester composition comprises a blockcopolymer of the polyester and the polymeric additive. By blockcopolymer, for example with reference to thepoly(6,6′-imino-bishexamethylene terephthalamide) polymeric additive andpolytrimethylene terephthalate, applicants are referring to a polymerformed by the polyester joined to the polymeric additive by a covalentbond.

The invention is further directed to an acid-dyed polyester compositionprepared by acid dyeing the composition described above, and a processcomprising (1) providing the polyester composition and (2) acid dyeingthe composition. When the polymeric composition comprises a triaminecontaining secondary amine unit(s), the primary dye site is the iminethereof.

The invention is also directed to a blend comprising (a) polyester; and(b) polymeric additive prepared from (i) triamine containing secondaryamine unit(s) or secondary amine salt unit(s) and (ii) one or more othermonomer and/or polymer units or a salt thereof. Alternatively, it isalso directed to a blend comprising (a) polyester; and (b) polyamide orpolyamide salt selected from the group consisting ofpoly-imino-bisalkylene-terephthalamide, -isophthalamide and-1,6-naphthalamide and salts thereof.

In addition, the invention is directed to a compound having thefollowing formula:

A or B, which may be the same or different, n, a and b are preferably asdescribed herein.

The invention is also directed to a process for preparing an aciddyeable polyester composition comprising the steps of (1) combiningabout 0.5 mole %-about 15 mole %, or the preferred amounts specifiedherein, of secondary amine units with a polyalkylene terephthalate,polyalkylene naphthalate or polyalkylene isophthalate in a polymericadditive wherein the amount of secondary amine units is effective topromote acid-dyeability, (2) mixing and heating the polymeric additiveand said polyalkylene terephthalate at a temperature sufficient to forma blend, and (3) forming the blend into a shaped article.

In one embodiment, the invention provides an acid-dyeable polyestercomposition comprising at least about 50 and up to about 99.5 mole % ofa polyalkylene terephthalate, and from about 0.5 mole %-about 15 mole %of secondary amine units in a polymeric additive. (Mole percentages arebased on the repeat units in the polyester composition.) This amount ofsecondary amine units is effective to promote acid-dyeability. Where thesecondary amine units form part of a polymeric additive, the comonomerwill also be present in about 0.5 mole %-about 15 mole %. The amount ofsecondary amine units effective to promote acid-dyeability is preferablyat least about 0.5 mole %, more preferably at least about 1 mole %, mostpreferably at least about 2 mole %, based on the polyester composition.The amount of secondary amine units effective to promote acid-dyeabilityis preferably about 15 mole % or less, more preferably about 5 mole % orless, based on the polyester composition.

In preferred embodiments of the invention, the polymeric additive maycomprise secondary amine units combined in substantially 1:1 molar ratiowith other monomer units, for example terephthalate or naphthalenedicarboxylate units, in order to construct the polymeric additive insuch a way that it may be easily combined with polyesters such aspolyalkylene terephthalate.

The secondary amine unit may preferably be obtained from a compoundselected from the group represented by H₂N(CH₂)_(m)NH(CH₂)_(n)NH₂ andits salts with a phosphorus-containing acid. Therein, m and n, which maybe the same or different, are integers, preferably at least two, morepreferably at least 4, preferably ten or less and preferably eight orless. The secondary amine unit may be an unsalinized amine, or may bepartly or completely salinized with a phosphorus-containing acid such asphosphorous acid, phosphoric acid or pyrophosphoric acid. Preferably theamine is bis(hexamethylene)triamine (m=n=6), and preferably it iscombined with a terephthalate or naphthalene dicarboxylate unit.Preferably the polyalkylene terephthalate polyester is polytrimethyleneterephthalate. In embodiments of the invention, the acid-dyeablepolyester composition of the invention is a block copolymer ofpolyalkylene terephthalate and a polymeric additive comprising secondaryamine units and terephthalamide or naphthylene dicarboxylamide units insubstantially 1:1 molar ratio.

The invention provides an acid-dyeable polyester composition that may beshaped into fibers, films, membranes and other useful shapes and iseasily acid dyed to a dye exhaustion of about 30%-about 80% or higher,preferably about 60%-about 80% or higher.

The invention also provides a process for preparing an acid-dyeablepolyester composition comprising the steps of: (1) combining secondaryamine units with polyalkylene terephthalate in polymeric additivewherein the amount of secondary amine units is effective to promoteacid-dyeability; (2) mixing and heating the polymeric additive and thepolyalkylene terephthalate at a temperature sufficient to form a blend,and (3) forming the blend into a shaped article.

The term “blend” as used herein to describe a composition is taken tomean a composition comprising a copolymer of the polyalkyleneterephthalate and the polymeric additive, which may also includeunreacted polyalkylene terephthalate and/or unreacted polymericadditive. The blend may comprise at least about 70%, more preferably atleast about 80%, and most preferably at least about 90%, of a copolymerof the polyalkylene terephthalate and the polymeric additive. Mostpreferably, the blend comprises at least 90% of a block copolymer of thepolyalkylene terephthalate and the polymeric additive. The shapedarticles may be stretched and heat treated to develop physicalproperties either before or after treatment with acid dyes.

DETAILED DESCRIPTION OF THE INVENTION

By “acid-dyeable” it is meant that the composition itself, or fiber,fabric, film or any other article (e.g., shaped articles) made with thecomposition has an affinity for acid dyes.

The polyester is preferably polyalkylene terephthalate, polyalkylenenaphthalate and polyalkylene isophthalate, and polyalkyleneterephthalate is most preferred. The preferred polyalkyleneterephthalates are fiber-forming linear condensation polymers havingcarboxyl linking radicals in the polymer chain. Polyethyleneterephthalate (“2GT”), polytrimethylene terephthalate (“3GT” or “PTT”),and polytetramethylene terephthalate (“4GT”) are preferred.Polytrimethylene terephthalate is especially preferred.

In the absence of an indication to the contrary, a reference to“polyalkylene terephthalate” is meant to encompass copolyesters, i.e.,polyesters made using 3 or more reactants, each having two ester forminggroups. For example, a copoly(ethylene terephthalate) can be used inwhich the comonomer used to make the copolyester is selected from thegroup consisting of linear, cyclic, and branched aliphatic dicarboxylicacids having 4-12 carbon atoms (for example butanedioic acid,pentanedioic acid, hexanedioic acid, dodecanedioic acid, and1,4-cyclo-hexanedicarboxylic acid); aromatic dicarboxylic acids otherthan terephthalic acid and having 8-12 carbon atoms (for exampleisophthalic acid and 2,6-naphthalenedicarboxylic acid); linear, cyclic,and branched aliphatic diols having 3-8 carbon atoms (for example1,3-propanediol, 1,2-propanediol, 1,4-butanediol,3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol,2-methyl-1,3-propanediol, and 1,4-cyclohexanediol); and aliphatic andaromatic ether glycols having 4-10 carbon atoms (for example,hydroquinone bis(2-hydroxyethyl) ether, or a poly(ethylene ether) glycolhaving a molecular weight below about 460, including diethyleneetherglycol). The comonomer typically can be present in the copolyester at alevel in the range of about 0.5-about 15 mole %. Isophthalic acid,pentanedioic acid, hexanedioic acid, 1,3-propane diol, and1,4-butanediol are preferred because they are readily commerciallyavailable and inexpensive.

Copoly(trimethylene terephthalate) made from 1,3-propanediol can also beused, in which case the comonomer(s) can be selected from the above list(except the aliphatic diols having 2-8 carbon atoms may be used andethanediol should replace 1,3-propanediol in the list).

The copolyester(s) can contain minor amounts of other comonomers, andsuch comonomers are usually selected so that they do not have ansignificant adverse affect on the amount of fiber crimp (in the case ofa spontaneously crimpable polyester bicomponent fibers) or on otherproperties. Such other comonomers include 5-sodium-sulfoisophthalate,for example, at a level in the range of about 0.2-5 mole %. Very smallamounts of trifunctional comonomers, for example trimellitic acid, canbe incorporated for viscosity control.

The polyester composition contains an effective amount of a secondaryamine unit to promote acid-dyeability. In the most preferred embodiment,the composition is prepared by melt blending polyester and polymericadditive comprising secondary amine. The most preferred polymericadditive for a polytrimethylene terephthalate (or polytrimethyleneterephthalate copolymer) is prepared from (i) triamine containing asecondary amine unit and (ii) one or more other monomer and/or polymerunits.

In a second embodiment, the secondary amine may be added to thepolyester, so that it is a comonomer(s). Polyester(s) containing suchcomonomers and polyester(s) without such a comonomer can be blended ormelt blended.

In a third embodiment, secondary amine may be mixed with polyester.

The particular amount of secondary amine unit used in the polyestercompositions may depend on which secondary amine unit containingcompound is used, which acid dye or dyes are used, and also theparticular composition of the acid-dyeable polyester of the invention.

Preferably, the secondary amine unit is present in the polymercomposition in an amount of at least about 0.5 mole %, more preferablyat least 1 mole %. The secondary amine unit is present in the polymercomposition in an amount preferably of about 15 mole % or less, morepreferably about 10 mole % or less, and most preferably 5 mole % orless, based on the repeat units in the polyester composition.

The polymeric additive composition is preferably formed from (i)triamine containing secondary amine unit and (ii) one or more othermonomer and/or polymer units. The molar ratio of (i) the triaminecontaining a secondary amine unit, and (ii) the one or more othermonomer and/or polymer units is approximately 1:1. It is preferable toadd a slight excess on the order of 1 mole %-10 mole % of the triamine(i) to promote end capping of the polymeric additive composition withprimary amine unit during synthesis. In this embodiment of theinvention, the amine groups on the end of the polymeric additivemolecule are available to form amide linkages with the polyestercomponent of the composition. An excess of (ii), the one or more othermonomer and/or polymer units, may also be used.

In embodiments of the polyester composition wherein the molar ratio ofthe (i) triamine containing a secondary amine unit and the (ii) one ormore other monomer and/or polymer units is approximately 1:1 in thepolymeric additive composition, the resultant molar concentration of the(i)-(ii) repeat units in the acid dyeable polyester compositions of theinvention is about 0.5 mole %-about 15 mole %, based on the polyestercomposition.

Preferably, the triamine (i) containing a secondary amine unit iscombined with (ii) terephthalate or naphthalene dicarboxylate monomerunit to form a polyamide having an imine group.

Preferably the acid-dyeable polyester composition is prepared by meltblending (a) polyester; and (b) polymeric additive prepared from (i)triamine containing secondary amine or secondary amine salt unit(s) and(ii) one or more other monomer and/or polymer units.

In another preferred embodiment, the acid-dyeable polyester compositionof claim 1 prepared by melt blending (a) a polyester; and (b) apolyamide or polyamide salt selected from the group consisting ofpoly-imino-bisalkylene-terephthalamide, -isophthalamide and-1,6-naphthalamide and salts thereof.

Preferably the polyamide comprises a compound having the followingformula:

Preferably A or B, which may be the same or different, are selected fromaliphatic or aromatic substituents. Preferably n is at least 3, morepreferably at least 10. Preferably n is 30 or less, more preferably 20or less. Most preferably n is 15. Preferably a is at least 1, morepreferably at least 3, most preferably at least 5. Preferably a is 20 orless, more preferably 12 or less. Preferably b is at least 1, morepreferably at least 3, more preferably at least 5. Preferably b is 20 orless, more preferably 12 or less.

Preferably a is at least 1, more preferably at least 3, most preferablyat least 5. Preferably a is 20 or less, more preferably 12 or less.Preferably b is preferably at least 3, most preferably at least 5.Preferably b is 20 or less, more preferably 12 or less.

Preferably, A or B, which may be the same or different, are selectedfrom alkyl and aryl and each may contain 0-20 alkyl units and 0-3 arylunits, provided that each contains at least one aryl unit or at leasttwo alkyl units. The alkyl and aryl units may be substituted orunsubstituted, straight or branched, etc., as long as the substituent(s)and branches don't substantially interfere with dyeing or other fiberproperties (e.g., the chain may contain an ether group).

In the most preferred embodiment, dimethyl terephthalate is combinedwith bis(hexamethylene) triamine to form apoly(6,6′-imino-bishexamethylene terephthalamide) having repeat unitsaccording to the formula:

Therein, n is preferably at least 3 and preferably 30 or less. Anysuitable polymeric synthesis route may be used to form apoly(6,6′-imino-bishexamethylene terephthalamide) polymeric additivecomposition in accordance with the present invention. Suitablealternative to dimethyl terephthalate (DMT) include the aliphatic andaromatic dicarboxylic acids or esters mentioned above as comonomers inmaking polyesters, such as terephthalic acid (TPA). Two or more suchmonomers can be used in forming the polymeric additive.

The secondary amine unit may be incorporated into the polymer chain ofthe polyester composition by melt blending the polymeric additive andother monomer units; for example, by melt blending terephthalate ornaphthalene dicarboxylate—second amine polymeric additive and polyester(e.g., polyalkylene terephthalate). Melt blending is preferably carriedout at about 230-about 270° C., most preferably about 260° C.

Diamines or other chain extenders can be added to the polymeric additiveto enhance its melt properties (e.g., higher melting temperature orviscosity). The final copolymer (i.e., when reacted with dimethylterephthalate (DMT) or another such compound) has improved intrinsicviscosity and/or tenacity. Any chain extender that extends the chain,preferably without substantially impacting dyeability or the otherproperties of the polymer composition, can be used. Preferred arediamines having the formula H₂N—(CH₂)_(n)—NH₂ wherein n is preferably 2or more, preferably 12 or less, more preferably 2-6, and most preferably6. Aromatic diamines having the same basic formula may also be usefulfor this purpose. The ratio of triamine to diamine is broad, with apreferred mole ratio of triamine:diamine of at least about 7:3, morepreferably at least about 4:1 and most preferably at least about 9:1.The diamines will fill the place of the triamines in the polymer chainof the polymeric additive, so in the case of a copolymer of diacid,diamine and triamine the ratio of diacid:(diamine and triamine) shouldbe about 1:1.

In a preferred embodiment, hexamethylene diamine (HMD) andbis(hexamethylene) triamine (BHMT) are used to formpoly(6,6′-imino-bishexamethylene terephthalamide-co-hexamethyleneterephthalamide) (PBHMT/PHMT). The product of DMT, BHMT and HMD is agrasslike polymer, which can be broken up and ground prior to use.

The polymeric additive (e.g., poly(6.6′imino-bis(hexamethyleneterephthalimide)) or poly(6,6′-imino-bishexamethyleneterephthalamide-co-hexamethylene terephthalamide)) can be salinized withany acid that stabilizes the amine or protects the amine group untildyeing is carried out. The acid is preferably added to the reactionmixture used to form the polymeric additive. Preferred are inorganicacids such as a phosphorus-containing acid. More preferably it issalinized with phosphorous acid or phosphoric acid, most preferablyphosphorous acid. The salinized additive has several benefits over theunsalinized additive. It improves fiber color, i.e., the degree ofwhiteness versus yellowness. It can reduce the IV loss during spinning,thus improving the fiber's physical properties. During dyeingoperations, it improves the degree of dye exhaust onto the fibers,increasing the deepness of color. The preferredpoly(6.6′imino-bis(hexamethylene terephthalimide) phosphorous acid saltis depicted below.

The Mn for the polyester (e.g., polyalkylene terephthalate) ispreferably at least about 10,000, more preferably at least about 20,000,and is preferably about 40,000 or less, more preferably about 25,000 orless. The preferred Mn depends on the polyester used.

The number average molecular weight (Mn) of the polymeric additive ispreferably at least about 1,000, more preferably at least about 3,000,and most preferably at least about 4,000, and preferably about 10,000 orless, more preferably about 7,000 or less, and most preferably about5,000 or less.

The Mn for the acid-dyeable polyester composition is preferably at leastabout 5,000, more preferably at least about 10,000, and preferably about30,000 or less, more preferably about 20,000 or less.

When the polyester composition is melt spun into fibers or filaments,long chain length linear polymer molecules are desirable.

The polymeric additive composition including the secondary amine unitshould be thermally stable.

Polyesters can be manufactured by the processes described in U.S. Pat.Nos. 5,015,789, 5,276,201, 5,284,979, 5,334,778, 5,364,984, 5,364,987,5,391,263, 5,434,239, 5,510454, 5,504,122, 5,532,333, 5,532,404,5,540,868, 5,633,018, 5,633,362, 5,677,415, 5,686,276, 5,710,315,5,714,262, 5,730,913, 5,763,104, 5,774,074, 5,786,443, 5,811,496,5,821,092, 5,830,982, 5,840,957, 5,856,423, 5,962,745 and 5,990265, EP998 440, WO 00/14041 and 98/57913, H. L. Traub, “Synthese undtextilchemische Eigenschaften des Poly-Trimethyleneterephthalats”,Dissertation Universitat Stuttgart (1994), S. Schauhoff, “NewDevelopments in the Production of Polytrimethylene Terephthalate (PTT)”,Man-Made Fiber Year Book (September 1996), and U.S. patent applicationSer. Nos. 09/016,444, 09/273,288, 09/291,960, 09/346,148, 09/382,970,09/382,998, 09/500,340, 09/501,700, 09/502,322, 09/502,642, 09/503,599,and 09/505,785, all of which are incorporated herein by reference.Poly(trimethylene terephthalate)s useful as the polyester of thisinvention are commercially available from E. I. du Pont de Nemours andCompany, Wilmington, Del. under the trademark Sorona and from ShellChemical Company, Houston, Tex. under the trademark Corterra.

Polymeric additive can be made from DMT according to the followingprocedure. DMT and BHMT are reacted at elevated temperature (up to about230° C.), preferably in the presence of water. The methanol by-productis distilled off. Then, the reaction is continued under vacuum at about0.2-about 1 mm Hg, preferably for about 30 minutes-about 1 hour,followed by cooling.

With TPA, a TPA salt with BHMT is formed in an aqueous solution, thissolution is then charged into an autoclave and heated up to about 200°C. at about 220 psig. Then, the pressure is released while maintainingthe temperature. This is followed by cooling.

Salinization is preferably carried out by mixing the polymeric additivestarting materials with the salinizing agent.

The preferred process for preparing the acid-dyeable polyestercomposition according to the invention comprises the steps of combiningthe polymeric additive with the polyester. The polymeric additive has anamount of a secondary amine unit effective to promote acid-dyeability.The polymeric additive and the polyester are mixed and heated at atemperature sufficient to form a blend, and the blend is formed into ashaped article. The mixing, heating and forming may be carried out byconventional equipment designed for that purpose such as extruders,banbury mixers or the like. The temperature should be above the meltingpoints of each component but below the lowest decomposition temperature,and accordingly must be adjusted for any particular composition ofpolyester and polymeric additive. The polyester and polymeric additivemay be heated and mixed simultaneously, pre-mixed in a separateapparatus before the heating occurs, or alternately may be heated andthen mixed.

The preparation of the polymeric additive and the acid-dyeable polyester(as well as the melt spinning of the acid-dyeable polyester) may becarried out at elevated temperatures in the range of about 200° C.-about270° C., most preferably about 250-260° C., depending on the particularpolyalkylene terephthalate employed in the acid dyeable polyestercomposition of the invention. The polymeric additive composition mustalso be compatible with the polyalkylene terephthalate composition inorder to be mixed and heated to form a blend.

When linear polymer forming conditions are employed and the polyester(e.g., polyalkylene terephthalate) and the polymeric additive are mixedand heated to form a composition, the primary amine functional group atthe end of the triamine molecule portion of the polymeric additivereacts to form an amide linkage with carboxyl groups of the polyester,leaving the secondary amine unit portion of the triamine essentiallyunreacted and free to form a dye site. Thus the secondary amine unitsbecome a part of the polymer chain and their presence in the polyesterfiber formed from the acid-dyeable compositions of the invention ispermanent and they are not easily removed by washing, dry cleaning orother processes used to launder fabric articles.

The acid-dyeable polyester composition of the invention typically doesnot discolor and/or thermally degrade. This is especially advantageouswhen the polyester composition is thermally processed, for example byextrusion from the melt, into shapes such as films, fibers or membranes.The dyed articles are superior in color fastness, brightness, weatherresistance, wear resistance and oxidation stability.

The polyester composition of the invention may be used to produce,acid-dyeable shaped articles, including high strength shaped articles.For example, in particular embodiments of the invention wherein thepolyester is polytrimethylene terephthalate, melt-spun filaments havinga tenacity of 2.0 g/d or more and a dye exhaustion of 30%-80%,preferably 60%-80% or higher, are obtained. This is quite remarkablebecause polytrimethylene terephthalate is generally considered adifficult polyester to spin into high strength fibers or filaments. Thisdifficulty may be attributable to its property of being a more amorphouspolymer than other polyalkylene terephthalates and therefore moredifficult to develop crystallinity and high strength by postmelt-spinning procedures. An added difficulty is that the use ofadditives to enhance one property of a polymer, e.g., acid-dyeability,often negatively affects other properties such as processability andstrength. However, in accordance with the invention, acid-dyeable, highstrength polyalkylene terephthalates, for example poly(trimethylene)terephthalate, fibers are obtained.

Other polymeric additives may be added to the acid-dyeable polyestercomposition to improve strength or facilitate post extrusion processing.For example, hexamethylene diamine may be added in minor amounts ofabout 0.5 mole %-about 5 mole % to add strength and processability tothe acid dyeable polyester compositions of the invention. Polyamidessuch as Nylon 6 or Nylon 6-6 may be added in minor amounts of about 0.5mole %-about 5 mole % to add strength and processability to theacid-dyeable polyester compositions of the invention.

The polyalkylene terephthalates may, if desired, contain additives,e.g., delustrants, viscosity boosters, optical brighteners, toningpigments, and antioxidants. Representative examples of linear,fiber-forming condensation polymers as embodied herein are set out inU.S. Pat. No. 4,001,190 to Tanikella et al. TiO₂ may be added to thepolyester or fibers. (See, e.g., U.S. Pat. Nos. 3,671,379, 5,798,433 and5,340,909, EP 699 700 and 847 960, and WO 00/26301, which areincorporated herein by reference.)

The compositions of this invention are useful in fibers, fabrics, filmsand other useful articles, and methods of making such compositions andarticles. By “fibers”, reference is made to items recognized in the artas fibers, such as continuous filaments, staple, and other choppedfibers. The fibers may be monocomponent (sometimes also referred to as“homofibers”), or bicomponent or other multicomponent fibers, includingsheath-core, eccentric sheath-core, and side-by-side fibers. Fabricsinclude knitted, woven and nonwoven fabrics. The polyester compositionsmay form a film or a film layer, etc.

Bulked continuous filaments and fabrics may be manufactured according tothe process described in U.S. Pat. Nos. 5,645,782 and 5,662,980, whichare incorporated herein by reference. Other documents describing fibersand fabrics, and their manufacture, include U.S. Pat. Nos. 5,885,909 and5,782,935, WO 99/06399, 99/27168, 99/39041, 00/22210, 00/26301,00/29653, 00/29654, 00/39374 and 00/47507, EP 745 711, 1 016 741, 1 016692, 1 006 220 and 1 033 422, British Patent Specification No. 1 254826, JP 11-100721, 11-107036, 11-107038, 11-107081, 11-189920, and11-189938, U.S. patent application Ser. Nos. 09/518,732 and 09/518,759,and H. L. Traub, “Synthese und textilchemische Eigenschaften desPoly-Trimethyleneterephthalats”, Dissertation Universitat Stuttgart(1994), H. L. Traub “Dyeing properties of Poly(trimethyleneterephthalate) fibres”, Melliand (1995), H. L. Traub et al., “MechanicalProperties of fibers made of polytrimethylene terephthalate”, ChemicalFibers International (CFI) Vol. 45, 110-111 (1995), W. Oppermann et al.“Fibers Made of Poly(trimethylene terephthalate)”, Dornbirn (1995), H.S. Brown, H. H. Chuah, “Texturing of Textile Filament Yams Based onPoly(trimethylene terephthalate)”, Chemical Fibers International, 47:1,1997. pp. 72-74, S. Schauhoff, “New Developments in the Production ofPolytrimethylene Terephthalate (PTT)”, Man-Made Fiber Year Book(September 1996), all of which are incorporated herein by reference.

The acid-dyeable polyester compositions can be used to make acid-dyeablepolyester bicomponent fibers, for example, bicomponent fibers comprisingpoly(ethylene terephthalate) and poly(trimethylene terephthalate) orpoly(ethylene terephthalate) and poly(tetramethylene terephthalate).Bicomponent fibers based on poly(ethylene terephthalate) andpoly(trimethylene terephthalate) are preferred. The polymeric additivecan be incorporated into either or both components. The components canbe arranged in a sheath-core, eccentric sheath-core, or side-by-siderelationship. When it is desired that the bicomponent fiber be crimpableon drawing, heat-treating, and relaxing to form a stretchable fiber, aneccentric sheath-core or side-by-side relationship can be used;side-by-side is preferred for higher crimp levels. The preferred 2GT/3GTbicomponent fibers can be manufactured as described in copending U.Spatent application Ser. No. 09/488,650 and U.S. patent application Ser.No. (09/708,314, filed on even date herewith), which are incorporatedherein by reference. One or both of the polyesters used in thesebicomponent fibers can be copolyesters. Comonomers useful in suchcopolyesters are described above with respect to the discussioncopoly(ethylene terephthalate) can be used to form copoly(ethyleneterephthalates) and copoly(trimethylene terephthalate). The comonomercan be present in the copolyester at a level in the range of about 0.5to 15 mole percent.

Acid dyeing is carried out using conventional techniques, such as thoseused for nylon.

The acid-dyeable polyester compositions according to the presentinvention contain secondary amines and are basic compounds. As such,they have a relatively high affinity for acid dyes and can be dyed in arange of colors. For example, the acid dyeable polyester compositionsmay be spun into fibers and dyed with C.I. Acid Blue 25 (C.I. 62055),C.I. Acid Red 4 (C.I. 14710), C.I. Acid Yellow 40 (C.I. 18950), C.I.Acid Green 25 (C.I. 61570), Tectilon Yellow 2G, Tectilon Red 2B,Tectilon Blue 4R, Lanaset Yellow 2R, Lanaset Red 2B, Lanaset Blue 2R andIrgalan premetallized acid dyes either alone or in combination. (Thesedyes are available from Ciba Specialty Chemicals Corporation, HighPoint, NC (Ciba).) Acid dye conditions according to the invention arepreferably from a pH of 3.5 or more, and a pH of 4.5 or more isespecially preferred ranging up to a pH of about 6.5. Of course, lowerpH values, e.g., 3.0, may be used if desired.

EXAMPLES

The following examples are presented for the purpose of illustrating theinvention, and are not intended to be limiting. All parts, percentages,etc., are by weight unless otherwise indicated.

Intrinsic Viscosity

The intrinsic viscosity (IV) was determined using viscosity measuredwith a Viscotek Forced Flow Viscometer Y900 (Viscotek Corporation,Houston, Tex.) for the polyester dissolved in 50/50 weight %trifluoroacetic acid/methylene chloride at a 0.4 grams/dL concentrationat 19° C. following an automated method based on ASTM D 5225-92. Thesemeasured IV values were correlated to IV values measured manually in60/40 weight % phenol/1,1,2,2-tetrachloroethane following ASTM D4603-96.

Dyeing Tests

Tectilon Acid Dyes in the Presence of Carrier

The as-spun yarn was knitted into a sock sample. A 5 gram sock samplewas put into a scouring solution containing 2 weight % Merpol-HCSnonionic surfactant (DuPont) and 1 weight % acetic acid at 72° C. for 20minutes. The sample was rinsed and placed into a 100 ml dye-bathcontaining 1 weight % of either Tectilon yellow 2G, Tectilon red 2B orTectilon blue 4R and 0.5% Tanalon HIW carrier (Sybron Chemicals,Birmingham, N.J.) at pH 3. The dye bath was heated to 100° C. for 90minutes. The sample was then rinsed with water and treated with 4%Erional PA solution (Ciba Corporation, Greensboro, N.C.) at pH 4.5-5.0at 82° C. for 20 minutes for dye fixing. The remaining dye solution wasmeasured in a visible spectrometer to calculate the exhaust.

Tectilon acid dyes were also run without a carrier in an identicalmanner to that above.

Lanaset Acid Dyes in the Absence of Carrier

The as-spun yarn was knitted into sock sample. A 5 gram sock sample wasput into a scouring solution containing 2% Merpol-HCS and 1% acetic acidat 72° C. for 20 minutes. The sample was rinsed and placed into a 100 mldye-bath containing 2% of either Lanaset Yellow 2R, Lanaset Red 2B, orLanaset Blue 2R at pH 3. The dye bath was heated to 100° C. for 90minutes. The sample was then rinsed with water and treated with 4%Erional PA solution at pH 4.5-5.0 at 82° C. for 20 minutes for dyefixing. The remaining dye solution was measured in a visiblespectrometer to calculate the exhaust.

Tensile Testing of Fiber Yarns

Tensile testing was carried out at 70° F. (21° C.), relative humidity65%, on an Instron type tensile tester. Yarn samples were twisted 3turns per inch and were tested at a crosshead speed of 3.6 inches/minuteat a gauge length of 6 inches. Five samples were run for each itemtested.

Example 1

Poly(6,6′-imino-bishexamethylene terephthalamide) (PBHMT) was preparedin a three-necked flask fitted with a mechanical stirrer, a thermocoupleand an air condenser. One mole (194.19 g) of dimethyl terephthalate(m.p. 140-142° C.) was combined with 1.02 moles (220 g) ofbis(hexamethylene) triamine (BHMT) (which had been purified bydistillation from High Purity Grade (95 weight %) BHMT to a colorlessproduct (m.p. 33-36° C., b.p. 163-165° C./4 mm)) and 1.8 moles (32.4 g)of water. The mixture was slowly heated to 210-230° C. in 40 minuteswhile removing methanol by-product. The reaction was then continued attemperature under a 0.2-0.5 mm Hg vacuum for about one hour. The mixturewas cooled and a glass-like product obtained which was broken up andground in a Willey mill through a ⅛″ (inch) mesh screen.

Polytrimethylene terephthalate (PTT) was prepared in a large-scale,batch two-vessel process. Molten dimethylterephthalate was added to1,3-propanediol and tetraisopropyl titanate catalyst (Tyzor TPT, DuPont)in a transesterification vessel and the temperature was increased to210° C. while methanol was removed. The resulting intermediate wastransferred to a polycondensation vessel where the pressure was reducedto one millibar (10.2 Kg/cm2) and the temperature was increased to 250°C. When the desired melt viscosity was reached, the pressure wasincreased and the polymer was extruded, cooled and cut into pellets. Thepellets were solid-phase polymerized to an intrinsic viscosity of 1.3 ina tumble dryer operated at 212° C.

Ground PBHMT was blended and reacted with PTT in a twin-screw spinningunit prior to spinning. Enough PBHMT (230 g) was blended and reactedwith twenty pounds (9080 g) of PTT to form a copolymer containing 1.5mole % BHMT. After dry mixing and blending the polymers at roomtemperature for 3-5 minutes, the molten copolymer was spun at 255° C.through a 34 hole spinneret with 10 mil diameter holes at 500meters/minute, followed by drawing 3× at 1500 meters/minute at 60°C.-90° C.

A control yarn of the PTT used in this Example 1 and applicable toExamples 2 and 3 was also spun on the twin-screw spinning unit at 255°C. through a 34 hole spinneret with 10 mil diameter holes at 500meters/minute, followed by drawing 3× at 1500 meters/minute at 60°C.-90° C.

The PTT fiber modified with 1.5 mole % BHMT was acid dyeable as shown bythe results of dye exhaust testing in Table 1. The control PTT yarn wasnot acid dyeable. Tensile properties are given in Table 2.

Example 2

Polytrimethylene terephthalate modified with 3.0 mole % BHMT wasprepared in a manner similar to Example 1 except that 459 g of PBHMT wasmelt blended and reacted with twenty pounds (9080 g) of PTT prior tospinning. This copolymer fiber was more deeply dyed than the fiber ofExample 1. Table 1 shows the dye results and Table 2 shows the tensileproperties.

Example 3

Polytrimethylene terephthalate modified with 4.5 mole % BHMT wasprepared in a manner similar to Example 1 except that 690 g of PBHMT wasmelt blended and reacted with twenty pounds (9080 g) of PTT prior tospinning. This copolymer fiber was more deeply dyed than the fiber ofExample 1. Table 1 shows the dye results and Table 2 shows the tensileproperties.

In the Tables below, mole % BHMT is equivalent to the mole % ofsecondary aliphatic amine unit.

TABLE 1 DYE EXHAUST vs. BHMT LEVEL BHMT % Lanaset Dye Exhaust % TectilonDye Exhaust Without Carrier % Tectilon Dye Exhaust With Carrier Example(mole %) Yellow 2R Red 2B Blue 2R Yellow 2G Red 2B Blue 4R Yellow 2G Red2B Blue 4R Control — 4.8 0 0 0 0 1.5 0 0 1.5 1 1.5 77.7 34.6 11.2 16.019.0 13.4 20.2 24.9 23.9 2 3.0 83.1 43.7 16.7 26.4 20.3 21.9 29.9 35.631.1 3 4.5 86.1 56.8 31.7 70.3 47.7 53.1 85.4 71.6 55.4

TABLE 2 YARN PHYSICAL PROPERTIES vs. BHMT LEVEL BHMT Yarn TenacityModulus Elongation Example (Mole %) IV (g/d) (g/d) (%) Control 0 0.822.6 23 64 1 1.5 0.80 2.3 23 62 2 3.0 0.70 1.8 23 66 3 4.5 0.64 1.7 19 62

Examples 4-6

Another series of PTT/PBHMT fibers were prepared as Example 1, but with1, 2 and 3 mole % BHMT. This series was acid-dyeable as expected.However, just as in Examples 1 to 3 (and shown in Table 2), intrinsicviscosity and tenacity apparently decreased with increased amounts ofPBHMT, as shown in Table 3.

Another control yarn was spun in the same manner as that for Example 1-3and is applicable to Examples 4-6. It was not acid-dyeable.

TABLE 3 YARN PHYSICAL PROPERTIES vs. BHMT LEVEL BHMT Yarn TenacityModulus Elong. Example Mole % IV g/d g/d % Denier Control — 0.92 2.4 2370 200 4 1.0 0.91 2.4 25 61 195 5 2.0 0.77 1.9 23 75 197 6 3.0 0.73 1.525 69 173

Examples 7 and 8

Intrinsic viscosity and tenacity were improved by adding small amountsof hexamethylene diamine (HMD) with the bis(hexamethylene) triamine(BHMT) to make a copolymer when reacted with dimethyl terephthalate(DMT). This copolymer poly(6,6′-imino-bishexamethyleneterephthalamide-co-hexamethylene terephthalamide) (PBHMT/PHMT) wasprepared in a manner similar to Example 1.

For Example 7, 242.7 g (1.25 moles) of dimethyl terephthalate (DMT) wasmixed with 255.8 g (1.188 moles) bishexamethylene triamine (BHMT) and11.53 g (0.069 moles, 10% excess) of a 69.3% aqueous hexamethylenediamine (HMD) solution and 40.5 g (2.25 moles) of water. The mixture wasgradually heated to 212° C. in 30 minutes at atmospheric pressure whileremoving methanol by-product. The pressure was reduced to 1.5 mm Hg andthe reaction continued for 10 more minutes. The reaction product wascooled and a glasslike polymer obtained, which was broken up and groundin a Willey mill through a ⅛″ mesh screen. The ground PBHMT/PHMTcopolymer (DMT/BHMT/HMD)(1.0/0.95/0.05 mole ratio) was blended andreacted with PTT in a twin-screw spinning unit prior to spinning. EnoughPBHMT/PHMT copolymer (39.9 g) was added to 2270 g of PTT to form acopolymer containing 1.0 mole % of DMT/BHMT/HMD (1.0/0.95/0.05 moleratio). Spinning was performed as in Example 1.

For Example 8, 42.7 g (0.225 moles) of dimethyl terephthalate (DMT) wasmixed with 42.7 g (0.197 moles) bishexamethylenetriamine (BHMT) and 4.8g (0.031 moles, 10% excess) of a 75% aqueous hexamethylene diamine (HMD)solution and 7.3 g (0.405 moles) of water. The mixture was graduallyheated to 228° C. in 34 minutes at atmospheric pressure while removingmethanol by-product. The pressure was reduced to 0.15 mm Hg and thereaction continued for 28 more minutes. The reaction product was cooledand a glasslike polymer obtained. The ground PBHMT/PHMT copolymer(DMT/BHMT/HMD) (1.0/0.875/0.125 mole ratio) was blended and reacted withPTT in a twin-screw spinning unit prior to spinning. Enough PBHMT/PHMTcopolymer (42.8 g) was added to 2270 g of PTT to form a copolymercontaining 1.0 mole % of DMT/BHMT/HMD (1.0/0.875/0.125 mole ratio).Spinning was performed as in Example 1.

After spinning, the fibers of Examples 7 and 8 appeared to be at leastas acid-dyeable as PBHMT modified fiber at the same level ofmodification. Intrinsic viscosity and tenacity were improved (Table 4)over the samples with PBHMT alone (Table 3).

The control yarn was the same as used in Examples 4-6. It was notacid-dyeable.

TABLE 4 YARN PHYSICAL PROPERTIES vs. BHMT LEVEL DMT/BHMT/HMD InPolymeric Additive - BHMT/HMT Mole % Yarn Tenacity Modulus Elong.Example Mole Ratio (in 3GT Composition) IV g/d g/d % Denier Control None0.92 2.4 23 70 200 7 1/0.95/0.05 1.0 0.96 2.6 24 51 200 8 1/0.875/0.1251.0 0.98 2.8 25 53 198

Example 9

A bicomponent fiber was prepared as follows: 342 g. PBHMT/PHMT polymerand 20 lb. of polytrimethylene terephthalate polymer (prepared as inExample 8 -1.3 IV polytrimethylene terephthalate with 0.75 BHMT/0.25 HMDadditive, having 2 mole % BHMT) were tumble mixed and compounded in atwin screw extruder at 230° C. The resulting pellets were dried at 120°C. for 16 hours, and poured into a hopper, and extruded through abicomponent spinneret into fiber at 255-265° C. In the same time,polyethylene terephthalate pellets (Crystar® 4415, DuPont) were addedinto another hopper, extruded at 275-285° C. into the same spinneretforming a bicomponent fiber with equal amounts of polyethyleneterephthalate and polytrimethylene terephthalate, only the lattercontaining PBHMT/PHMT acid dye modifier. The polymers were melt spunthrough a 68 hole spinneret to form 34 side-by-side snowmancross-section bicomponent filaments (50/50 v/v) just below the spinneretface. (An example of such a cross-section is illustrated in FIG. 4 ofU.S. Pat. No. 3,671,379.) The spinneret was maintained at 275° C. Thefilaments were spun past a quench zone 66 inches long through ambienttemperature cross-flow air moving at 0.14 ft.sec, past a finish tip tolubricate the yarn, and onto a 60° C. feed roll with a surface speed of842 meters/minute. This yarn was then drawn 3.8× with a 90° C. draw rollwith a surface speed of 3200 meters/minute, and then onto a 160° C.heat-treating roll operating at 3200 meters/minute, over a 3200meters/minute quench roll operating at ambient, and onto a windup. Theyarn had 34 filaments, and upon hot relaxation, it spontaneouslydisplayed helical crimp. The physical properties of the resultingbicomponent yarn are shown in Table 5.

Crimp contraction levels were measured immediately after drawing andheat-treating by hanging a loop of fiber from a holder with a 1.5mg/denier (1.35 mg/dtex) weight attached to the bottom of the loop andmeasuring the length of the loop. Then a 100 mg/den (90 mg/dtex) weightwas attached to the bottom of the loop, and the length of the loop wasmeasured again. Crimp contraction was calculated as the differencebetween the two lengths, divided by the length measured with the 90mg/dtex weight.

In this example, the tensile property was tested by twisting three turnsper inch, running at 3 inch/minute crosshead speed and 5 inch gaugelength.

The control was a bicomponent fiber made as above, except that it didnot contain polymeric additive.

TABLE 5 Physical Properties of 3GT/2GT Bicomponent Yarns PolymericAdditive BHMT Mole Ratio Mole Tenacity Modulus Elong. Crimp ExampleDMT/BHMT/HMD % g/d g/d % % Denier Control None — 3.64 NA 18.74 66 73.6 91.0/0.75/0.25 2.0 2.55 23.19 13.20 17 72.6 9 (repeat) 1.0/0.75/0.25 2.02.77 23.74 15.49 21 72.9

The tenacity of the bicomponent yarn containing the additive wasdecreased compared to the Control sample, but the overall physicalproperties shown are within an acceptable range for many applicationsrequiring a dyeable bicomponent fiber.

The yarn was knitted into socks and dyed with acid dyes into light grayand beige color. The color looked solid even though the polyethyleneterephthalate part was not modified for acid dyeability.

Examples 10A and 10B

A PBHMT/PHMT polymer salinized with phosphorous acid (H₃PO₃) wasprepared as follows:

A 2 liter three-neck flask, equipped with a mechanical stirrer, athermal couple and an air condenser, was charged with 310.4 g (1.6moles) dimethyl terephthalate (DMT), 258.5 g (1.2 moles)bis(hexamethylene) triamine (BHMT), and 60.4 g (0.33 mole) of 69.7%hexamethylenediamine (HMD) solution, and 98.4 g H₃PO₃ (1.2 moles) in 50g (2.78 moles) water. The mixture was heated slowly to 210-230° C. for40-60 minutes while methanol was distilled. The reaction was thencontinued under vacuum at about 0.2-0.5 mm Hg for about 1 hour. Theglass-like polymer product was then collected and ground after coolingdown to room temperature.

The resultant polymer was compounded with PTT pellets at 220° C. at 2and 4 BHMT mole % levels (Examples 10A and 10B, respectively), and spuninto fiber at 260° C. The physical properties of the resulting yarn areshown in Table 6 below. Dye exhaust tests are shown in Table 8.

Example 11

A polymer was prepared according to the procedure in Example 10, exceptthat the monomer (mole) ratio was DMT/BHMT/HMD/H₃PO₃=1/0.8/0.2/0.8. Yarnphysical properties are shown in Table 6. The yarns were knitted intosocks and dyed at 100° C. by Lanaset dyes as shown in Table 7.

Example 12

A PBHMT/PHMT polymer salinized with phosphoric acid (H₃PO₄) was preparedas follows:

A 2 liter three-neck flask, equipped with a mechanical stirrer, athermal couple and an air condenser, was charged with 310.4 g (1.6moles) dimethyl terephthalate (DMT), 275.7 g.(1.28 moles)bis(hexamethylene) triamine (BHMT), and 55 g. (0.33 mole) of 69.7%hexamethylenediamine (HMD) solution, and 147.6 g. 85% H₃PO₄ (1.28moles), and 43.2 g. (2.4 moles) water. The mixture was heated slowly to210-230° C. for 40-60 minutes while methanol was distilled. The reactionwas then continued under vacuum at about 0.2-0.5 mm Hg for about 1 hr.The glass-like polymer product was then collected and ground aftercooling down to room temperature.

The polymer was mixed with PTT pellets and spun into fiber at 260° C.Physical properties of the resulting fibers are shown in Table 6. Theyarns were knitted into socks and dyed at 100° C. by Lanaset dyes asshown in Table 8. Dye exhaust tests are shown in Table 8.

Controls 1 and 2 were prepared with the same 3GT (without polymericadditive).

TABLE 6 YARN PHYSICAL PROPERTIES vs. ADDITIVE LEVEL Additive Mole RatioDMT/BHMT/HMD/ BHMT Fiber Tenacity Modulus Elongation Example H₃PO₃ orH₃PO₄ Mole % IV g/d g/d % Denier Control #1 None — 0.927 3.01 26.1345.92 97.2 10A 1.0/0.75/0.25/0.75 2.0 0.840 2.44 25.64 46.88 97.6(H₃PO₃) 10B 1.0/0.75/0.25/0.75 4.0 0.774 2.32 23.84 49.72 93.2 (H₃PO₃)Control #2 — — 0.892 2.60 23.42 70.62 94.9 11 1/0.80/0.20/0.80 2.0 0.7972.38 23.04 61.84 97.7 (H₃PO₃) 12 1.0/1.0/0/100 2.0 0.854 2.37 24.0669.29 183.9 (H₃PO₄)

The addition of phosphorous acid or phosphoric acid reduced the IV lossduring spinning. At 2 mole %, the yarn IV can be maintained at 0.84 inthe presence of phosphorous acid (Example 10A), or 0.85 in the presenceof phosphoric acid (Example 12), while the IV can only be kept at 0.77in the absence of either acid (Example 5). As a result, the fiberproperties are improved too as shown in the above table. The physicalproperties of the fiber were decreased with increased amounts of theadditive, as expected, but are close to the Control and are consideredgood, with tenacities well above 2.0 g/d.

The yarns were knitted into socks and dyed at 100° C. by Lanaset dyes asshown in Table 8.

Color was measured using a Varian Cary 5 uv/vis/nir spectrophotometerwith 110 mm integrating sphere (Varian, Inc., Palo Alto, Calif.). Thismethod involved collecting a baseline for 100% and 0% reflectance usingPTFE reference disk, and then replacing the reference disk with thesample. Diffuse reflectance uv/vis spectrum is collected. The spectraldata, xy pairs, are processed using Varian Color Calculation softwareversion 5.1.

In the following table, the L is a measurement of degree of whiteness,100 means black, 0 means white; b is a measurement of red and green; ais a measurement of blue and yellow; Read “L”,“a”, “b” means the numbersfrom the instrument reading;

L calc, a calc, and b calc are calculated numbers from the read numbers;and WI and YI are white index and yellow index calculated from the L, a,b numbers by the defined equations.

TABLE 7 COLOR READINGS OF SOCK SAMPLES vs. H₃PO₃/H₃PO₄ LEVEL H₃PO₃ AExample H₃PO₄ Read “L” Read “a” Read “b” L calc. Calc. b calc. WI YI  5None 89.99 −2.61 11.65 91.5 −2.0 4.7 59.4 7.6 11 0.8 H₃PO₃ 88.94 −0.684.54 90.5 −0.5 1.8 72.4 3.2 equ. To BHMT 12 0.8 H₃PO₄ 88.24 −0.60 3.4690.71 0.6 3.5 60.8 5.5 equ. To BHMT

The above 3 samples all contain 2 mole % BHMT polymer but with differentcompositions. Phosphorous acid improves fiber color, as shown in theabove table. The white index (WI) increased significantly and the yellowindex (YI) decreased. Phosphoric acid also imparts some improvement, butless than phosphorous acid.

TABLE 8 DYE EXHAUST vs. BHMT/H₃PO₃ or H₃PO₄ LEVEL Additive Mole RatioDMT/BHMT/HMD/ BHMT % Lanaset Dye Exhaust Example H₃PO₃ or H₃PO₄ mole %Yellow 2R Red 2B Blue 2R 10A 1.0/0.75/0.25/0.75 2.0 82.1 42.4 22.7 10B1.0/0.75/0.25/0.75 4.0 89.3 54.2 30.5 12  1.0/1.0/0.0/0.8 2.0 80.7 40.619.4

The above examples show that the % dye exhaust improves with anincreased amount of the phosphorous acid additive (Example 10B vs.Example 10A). The % dye exhaust is slightly lower with the phosphoricacid additive than with phosphorous acid (Example 12 vs. Example 10A),but still good.

Example 13

Polymeric additive was made using terephthalic acid (TPA) as follows bycharging a 35 pound autoclave with:

-   -   3,277.7 grams (19.73 moles) TPA    -   1,294.0 grams (15.78 moles) phosphorous acid    -   3,398.9 grams (15.78 moles) BHMT    -   459.0 grams (3.95 moles) HMD    -   14,528 grams water        The mixture was stirred at 15 RPM and heated up to 230° C. and        250 psi. Then the pressure was reduced to atmosphere within 1        hour, while holding the temperature at 230° C. The polymer melt        was discharged into a drum containing dry ice under venting.        After cooling, the polymer was dried at room temperature        overnight and ground into flakes. This polymeric additive was        suitable for acid dyeing polyester.

The foregoing disclosure of embodiments of the present invention hasbeen presented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formsdisclosed. Many variations and modifications of the embodimentsdescribed herein will be obvious to one of ordinary skill in the art inlight of the above disclosure. The scope of the invention is to bedefined only by the claims appended hereto, and by their equivalents.

1. A polymeric additive for incorporating secondary amine units into the polymer chain of a polyester composition comprising a compound having the following formula:

wherein A or B, which may be the same or different, are select from aliphatic or aromatic substituents, wherein n is 10-30, a is 3-20 and b is 3-20, wherein the polymer composition comprises about 0.5 mol % to about 15 mol % secondary amine units.
 2. The polymeric additive of claim 1 wherein n is 10-20.
 3. The polymeric additive of claim 2 wherein A or B, which may be the same or different, are selected from alkyl and aryl and each may contain 0-20 alkyl units and 0-3 aryl units, provided that each contains at least one aryl unit or at least two alkyl units.
 4. The polymeric additive of claim 1 wherein n is
 15. 5. The polymeric additive of claim 1 wherein a is 5-20.
 6. The polymeric additive of claim 1 wherein a is 5-12.
 7. The polymeric additive of claim 1 wherein b is 5-20.
 8. The polymeric additive of claim 1 wherein b is 5-12.
 9. The polymeric additive of claim 1 wherein a is 5-20 and b is 5-20.
 10. The polymeric additive of claim 9 wherein A or B, which may be the same or different, are selected from alkyl and amyl and each may contain 0-20 alkyl units and 0-3 aryl units, provided that each contains at least one aryl unit or at least two alkyl units.
 11. The polymeric additive of claim 1 wherein a is 5-12 and b is 5-12.
 12. The polymeric additive of claim 11 wherein A or B, which may be the same or different, are selected from alkyl and aryl and each may contain 0-20 alkyl units and 0-3 aryl units, provided that each contains at least one aryl unit or at least two alkyl units.
 13. The polymeric additive of claim 1 wherein n is 10-20, a is 5-20 and b is 5-20.
 14. The polymeric additive of claim 13 wherein A or B, which may be the same or different, are selected from alkyl and aryl and each may contain 0-20 alkyl units and 0-3 aryl units, provided that each contains at least one aryl unit or at least two alkyl units.
 15. The polymeric additive of claim 1 wherein n is 10-20, a is 5-12 and b is 5-12.
 16. The polymeric additive of claim 15 wherein A or B, which may be the same or different, are selected from alkyl and aryl and each may contain 0-20 alkyl units and 0-3 aryl units, provided that each contains at least one aryl unit or at least two alkyl units.
 17. The polymeric additive of claim 1 wherein A or B, which may be the same or different, are selected from alkyl and aryl and each may contain 0-20 alkyl units and 0-3 aryl units, provided that each contains at least one aryl unit or at least two alkyl units.
 18. The polymeric additive of claim 1 further comprising a compound formed from hexamethylene diamine and bis(hexamethylene triamine) and a diacid, wherein the ratio of hexamethylene diamine and bis(hexamethylene triamine) to the diacid is about 1:1.
 19. The polymeric additive of claim 1, wherein the polymeric composition comprises about 0.5 mol % to about 10 mol % secondary amine units.
 20. The polymeric additive of claim 19, wherein the polymeric composition comprises about 1 mol % to about 10 mol % secondary amine units.
 21. The polymeric additive of claim 20, wherein the polymeric composition comprises about 2 mol % to about 5 mol % secondary amine units.
 22. A polymeric additive for incorporating secondary amine units into the polymer chain of a polyester composition comprising poly(6,6′-imino-bishexamethylene terephthalamide) having repeat units according to the formula:

wherein n is 10-30, wherein the polymeric composition comprises about 0.5 mol % to about 15 mol % secondary amine units.
 23. Poly(6,6′-imino-bishexamethylene terephthalamide) as claimed in claim 22 wherein n is 10-20.
 24. Poly(6,6′-imino-bishexamethylene terephthalamide) as claimed in claim 22 wherein n is
 15. 25. A polymeric additive for use in forming an acid-dyeable polyester composition, said polymeric additive prepared from a triamine containing one or more secondary amine salt units and one or more other units selected from monomer units, polymer units and salts thereof, said polymeric additive comprising secondary amine units in a ratio of about 1.005:1 to about 1.15:1 to other monomer units, wherein the amount of secondary amine units is effective to promote acid-dyeability of said polyester composition.
 26. The polymeric additive of claim 25 wherein said other monomer units are terephthalate units or naphthalene dicarboxylate units.
 27. The polymeric additive of claim 25, comprising about a 1 mole % to about a 10 mole % excess of said triamine such that said polymeric additive is end capped with primary amine units. 